The stone cutting industry in Mahallat, Iran is a big business - in fact, it accounts for almost half the city's economy. Unfortunately, the cutting process produces a lot of wasted stone that can't be used. Tehran-based Architecture by Collective Terrain wanted to do make use of this "unusable" stone, so they built an apartment building out of the remains. Apartment No. 1 in downtown Mahallat is a contemporary stone building with eight 3-bedroom apartments set atop a street-level retail space. Not only is the project stunning, but it also shows the city that their scrap stone is really not waste at all.

The region around Mahallat has considerable travertine deposits, which is mined and cut into tile in factories. However the process of cutting tile is incredibly energy intensive, and the production of one tile wastes a tile’s worth of material. These scraps are considered unusable and sent to the dump.

When designing an apartment building for the center of Mahallat, Architecture by Collective Terrain wanted to show the town that these “scraps” could still be used. They collected left-over stones from different mines and combined them to create a building with a multicolored texture and organic pattern. The five-story project features retail on the first floor and four stories of apartments. Each floor has two 3-bedroom apartments, and the local stone used on the exterior is also brought into the interior to create a unified theme.

The stones provide thermal mass to slow the transfer of heat throughout the day, and operable shading devices help control sunlight and heat gain. When the shades are open during the winter, more light and heat reaches into the interior. In the hot summer months, the shades can be closed to keep the sun out. Angled facades near windows help control the amount of daylight that enters the interior. The project was completed in 2010 and it has already influencing the town and local builders to make use of this recycled stone. Apartment No. 1 has been added to the shortlist for the 2013 Aga Khan Architecture Award.